The State Emergency Services yesterday recommended about 600 residents evacuate as the already swollen Cooma Creek and Cooma Back Creek threatened to flood.

Some locals spent their third straight night away from home, staying at the evacuation centre or with friends on higher ground.

More than 100 millimetres of rain was recorded in the mountain town last week.

But relief was in sight with downpours forecast to ease this afternoon and tomorrow.

Main street shops were yesterday sandbagged as business owners watched the skies for an indication of the coming conditions.

Video Ezy employee Chris Anthony said the store had been waterproofed every night since Thursday. ''The general feeling has been not to worry but be prepared just in case,'' Mr Anthony said.

Big B's Diner staff Hans and Sue Pechotsch yesterday stationed sandbags across the front door but hoped it was unnecessary.

Ms Pechotsch moved to Cooma from Melbourne in 2005 and had never seen the town threatened by floodwater.

''Thursday was scary [and] I'm still worried because everything is waterlogged already,'' she said.

Rural Fire Service media officer Matthew Atts said SES volunteers have received more than 150 calls for help since Thursday. He said 10 SES volunteers and two fast-water technicians were monitoring the situation.

Telstra has offered to help residential, mobile phone and small business customers affected by flooding in and around Cooma with a free call diversion and one-off $50 mobile phone credits to customers without a landline.

The offers apply until network damage caused by the flooding is repaired, or customers remain evacuated - up to a maximum of three months from the date of the natural disaster.

Capital South East area general manager Chris Taylor said little damage to key Telstra infrastructure had been reported so far, but technicians would be on call to recover impacted services.

''We understand this is a terrible time for anyone who has been affected by these floods and hopefully this package will help people as they work through this crisis,'' he said.

■ Affected customers should call 132 203.