Environmental protesters have spent the night camped outside the construction site of a gas pipeline in Trebanos, in the Swansea Valley.
One group of protesters have set up camp at the construction site
Many of the group, who call themselves Rising Tide, were involved in a protest at the same site in November.
They say the 150-mile (241 km) gas pipeline being built from Milford Haven to Gloucestershire will damage the environment.
Contractor the National Grid has said it will hold talks with activists.
Last November protesters occupied part of the pipeline for more than a week.
The latest site under occupation is one where blasting with explosives was originally planned. The Department of Trade and Industry (DTI) refused permission in November, saying it shared residents' concerns that the route of the pipeline was too close to home.
Instead National Grid is planning to dig a shaft for the pipeline by mechanical "peckers".
One group of protesters was camped on a public footpath which crosses an access road, stopping works vehicles getting through.
Another group, who said they were from Gloucestershire, was camped higher on the site, by a section of the pipeline.
They were being supported by Trebanos villagers who took part in demonstrations last year against the pipeline.
Trebanos resident Rachel Evans said the group were "highlighting an issue that hasn't gone away".
She said: "When you have the LNG pipeline actually going past your back door or back garden, then obviously you are going to have a different viewpoint from people who are living in a safer zone."
Caroline Davidson of the National Grid said a "small number" of demonstrators were involved in the latest protest.
"Safety is paramount to National Grid at all times and in all aspects of our work," she said.
"However, we will be continuing construction of our essential natural gas pipeline when it is safe to do so."
Ms Davidson said contractors would be looking to talk to the protesters to discuss what concerns they had.
Some residents opposed the use of explosives at Trebanos
When complete, the pipeline will carry gas which has been imported as Liquefied Natural Gas (LNG) at Milford Haven and will eventually provide 20% of the UK's energy supply.
Some residents in Milford Haven formed a campaign group, Safe Haven, to try to prevent two LNG terminal being built in the town, citing concerns over safety. An offshoot campaign, Safe Haven Network, has also taken part in protests against the pipeline.
In November the protesters occupied a section of the pipeline at Trebanos after initially being given permission to go onto the land by the owner.
The group, who said the pipe was not ecologically friendly or safe, lived in the pipeline for over a week, in cramped and wet conditions.
The action received support from many local people and some supplied food and clothes to the campaigners.