Some homes in Abergavenny were flooded on Monday

Arriva Trains Wales put on a replacement bus service between Newtown and Machynlleth after the line flooded.

By mid afternoon on Friday there were six flood warnings and 11 flood watches issued by Environment Agency Wales.

Exposed areas in the west are most at risk with up to 100mm (4in) of rain possible by the end of Saturday.

Roads and homes were flooded and three people were rescued from cars after heavy rain in Wales earlier this week.

Environment Agency Wales had two flood warnings and five flood watches in force in Wales on Friday morning.

The Met Office issued an early severe weather warning for Friday and Saturday in Wales.

It advised people to take extra care and refer to the latest Environment Agency information and to Traffic Wales for advice on road conditions.

In Carmarthenshire, teams of council staff are on standby in case of any emergencies.

The advice is to keep a close eye on the forecast Derek Brockway, BBC Wales weatherman

Environment executive board member Pam Palmer said: "We are advising motorists to take extra care and be mindful of the driving conditions, particularly during rush hours.

"Travel conditions could be difficult in many parts of Carmarthenshire."

The heaviest rain is likely to fall on the exposed upland areas of Wales like the Brecon Beacons, the Cambrian mountains and Snowdonia, said BBC Wales weatherman Derek Brockway.

"The problem is we have already had a fair amount of rain this month and some rivers are swollen so it won't take too much more rain to cause further problems, especially in low-lying areas," he said.

"Strong winds will be an additional hazard.

"The advice is to keep a close eye on the forecast."

Many rivers are already very full and Doug Whitfield, national flood warning duty officer at the Environment Agency, said officers were closely monitoring the rivers Wye, Dee and Severn.

On Monday, three people were rescued from cars after becoming stranded in flooding near Crymych, Pembrokeshire and in Newtown and Caerhowell in Powys.

Three homes in Abergavenny, Monmouthshire, were flooded and a landslide also blocked a road in Tintern.

Meanwhile, the Welsh Conservatives have called for the establishment of an all-Wales flood defence agency.

Darren Millar said flooding problems would be better dealt with by one body rather than the current system which sees the Environment Agency, local authorities, landowners and the Welsh Assembly Government sharing responsibility.

Capel Curig in Gwynedd has had more than twice the average rainfall for the last four weeks.