(Recasts, adds Tsipras quote, details, new election poll)
By Angeliki Koutantou and George Georgiopoulos
ATHENS, Sept 4 (Reuters) - Greek leaders fighting an unexpectedly close election campaign traded barbs on Friday over the migration crisis as about 200 unregistered migrants threw stones and scuffled with police and coastguard officials on the island of Lesbos.
Former Prime Minister Alexis Tsipras, whose poll lead has crumbled in recent days, blamed the rival New Democracy party for not doing enough while in power to prepare for the crisis now engulfing Europe. New Democracy leader Evangelos Meimarakis had accused Tsipras's government of indifference to the issue during its seven months in office.
Referring to a picture of a dead Syrian migrant child that horrified Europe, Tsipras said: "Yesterday's photo of horror, which has shaken the whole world, shows the big irresponsibility and shame of ... especially New Democracy, who tried to capitalise on the problem."
In a televised address, he added: "New Democracy ... handed over to us absolutely nothing to tackle the refugee problem while it had been obvious that waves of refugees were expected to come."
European Union officials visiting Greece promised more help to such frontline countries in assisting the hundreds of people, many fleeing war and poverty, arriving on Greek shores every day.
In Lesbos, "about 200 migrants that were not registered tried to get on a ferry at the port and they were pushed back by the police and the coastguard," coastguard spokesman Nikos Lagkadianos said.
European Commission First Vice President Frans Timmermans told reporters in remarks broadcast from the Greek island of Kos that Brussels would next week propose an expanded scheme to relocate asylum seekers around the bloc.
Athens will receive 33 million euros ($37 million) from Brussels in the first tranche of funds Greece has asked for to assist migrants, Timmermans said, adding that countries should also speed up the process of weeding out bogus asylum claims. The interim Greek government this week asked for 700 million euros of funding in total.
"So if we are to stay in touch with our own humanity and keep support from the European population for a humane asylum policy, we have to make sure that people who do not have the right to asylum are identified quickly and sent back from where they came from," Timmermans said.
"If we do not succeed in doing that, the asylum policy will collapse and that would be a tragedy for our European values."
Help can't come soon enough for the mayor of Lesbos' main town, who on Friday made a public plea for aid and for Athens to declare a state of emergency on the island.
"For four months now I have been saying that I am holding a bomb in my hands and the fuse is slowly burning," Spyros Galinos, mayor of Mytilini told state TV ERT.
"Two days ago I sent a letter asking to declare the island in a state of emergency. Today I am asking the prime minister for immediate relief measures, the situation has become unmanageable."
Conditions for refugees on the islands have been criticised in the past, including by the United Nations' refugee agency. On Friday, Amnesty International said it had witnessed a violent attack on the refugees in Kos, by 15 to 25 people wielding bats and shouting abuse.
A ship carrying 2,493 migrants collected from various Greek islands arrived in Athens earlier on Friday.
"It is a very difficult trip," said Mohad, a 27-year-old refugee from Damascus. "We were very hungry and thirsty on the Farmakonisi island. Actually we are suffering from a lot of things. But we hope ... Germany or Sweden or any country (will) protect us, OK?"
The latest opinion poll published on Friday showed New Democracy taking a tiny lead over Tsipras's Syriza party before a Sept. 20 election that Tsipras called to secure a fresh mandate for a tough bailout programme. ($1 = 0.8977 euros) (Additional reporting by Georgia Kalovyrna and Michele Kambas; Writing by Matthias Williams; Editing by Louise Ireland and Ruth Pitchford)