Independent Wentworth MP Kerryn Phelps will on Monday concede the blue ribbon eastern suburbs seat to her Liberal opponent Dave Sharma.
A source close to Dr Phelps said it was a disappointing result because the Liberals poured money into the seat «while refusing to put their candidate up for any forums or debates».
It is understood Dr Phelps has not called Mr Sharma to offer her congratulations but will make a statement at midday in Double Bay.
The race for seat has been neck and neck with Mr Sharma leading the sitting MP by just 1751 votes on Monday morning.
Mr Sharma has 51.16 per cent of the vote on a two-party preferred basis while Dr Phelps has 48.84 per cent with about 75 per cent of the vote counted.
Mr Sharma, the former ambassador to Israel, was confident he could claw back the seat for the Liberals after Dr Phelps wrestled it from the party at a by- election in October sparked by the dumping of ex-Liberal prime minister Malcolm Turnbull.