Real Madrid superstar Bale scored a double for the Dragons as they opened their 2018 World Cup qualifying campaign with a 4-0 win over Moldova in Cardiff on Monday night.
The goals were Bale's 23rd and 24th of his 62-game international career and at the age of just 27, will have no troubles beating Liverpool legend Rush's current record of 28 goals, which were scored in 73 matches for the British nation.
"He will break it in this campaign," said Coleman.
"If you look at Gareth's record in the last two years there is every chance it will happen.
"Gareth may not even know about it because he comes along and just fits in with the furniture.
"He will not think he has to do it, but there is every chance that can happen in the next nine games.
"It is a nightmare for opposition managers because he can change your life in an instant with one bit of skill."
Bale's brace saw him move past Trevor Ford and Ivor Allchurch into second place on Wales' all-time scoring chart.