From the first week of January next year 22 weekend trains on the South Coast line will be doubled from four to eight carriages.

The move sees the fulfillment of a commitment Transport and Roads Minister Andrew Constance made back in February this year.

"This was in response to a huge spike in demand, with the number of customers travelling on the most popular South Coast line weekend trains increasing by nearly 40 per cent since 2016," Mr Constance said.

"It should also stimulate further growth for local businesses, with more and more tourists encouraged to make the trip down from Sydney for some sightseeing."

However, Cr Honey said there's no problem getting day trippers to come to Kiama.

"This will certainly encourage more day-trippers and they do add to the economy," he said.

"But we prefer they stay a night or two. The council is trying to target longer-stay people for tourism."

Nine services from Kiama to Bondi Junction will receive the boost to eight cars, as well as two leaving Wollongong and heading to Bondi and 11 services going the other way.

The services with extra carriages from January 5 are:

Kiama to Bondi Junction: Leaving 5:57am, 7:00am, 9:56am, 11:05am, 11:56pm, 1:05pm, 3:56pm, 5:05pm and 5:56pm.

Wollongong to Bondi Junction: Leaving 4.56am and 5.31am

Bondi Junction to Kiama: 7:13am, 8:13am, 9:13am, 10:13am, 1:13pm, 2:13pm, 3:13pm, 4:13pm, 7:13pm, 8:13pm and 9:13pm.