UPDATE 1-Novae Group says Q3 improvements may offset H1 losses

* Sees underwriting diversification helping in 2010

* Nine-month gross written premium up 15 pct

* Sees rate increases helping aviation reinsurance unit

* Remains cautious about specialty business

* Shares down 1 pct (Adds details)

Nov 11 (Reuters) - British non-life insurer Novae Group Plc (NVA.L) said on Wednesday a healthy third-quarter profit helped in offsetting losses at its credit and aviation reinsurance business in the first half.

While Novae expects its aviation reinsurance business to benefit from rate increases in the fourth quarter, it remains cautious about the specialty business, the largest of its four reporting segments.

Novae, which had swung to a pretax loss of 2.1 million pounds ($3.52 million) in the first half of the year, said it expected increasing diversification of its underwriting portfolio to help the company in 2010.

"If the steady improvements enjoyed during the third quarter are maintained for the remainder of the year, we can counter the disappointments of the first half," Chief Executive Matthew Fosh said in a statement.