Differences of opinion between senior Labour figures over Brexit have been defended by a Welsh Government minister.
Mark Drakeford said there were varying views within Labour because "the water is genuinely muddy" on the UK's future relationship with the EU.
The party's shadow trade secretary Barry Gardiner has said staying in the customs union would be "a disaster".
But Labour leader Jeremy Corbyn is not ruling out continued membership of it.
In the customs union, countries agree to apply the same tariffs to goods from outside the union.
Once goods have cleared customs in one country, they can be shipped to others in the union without further tariffs being imposed.
But staying in the customs union would mean the UK could not negotiate free trade deals with other countries.
In a Commons vote in June, 50 Labour MPs backed continued membership of both the customs union and single market.
Mr Corbyn has said the UK must leave the single market as it is "inextricably linked" to EU membership.
Labour's general election manifesto called for the benefits of the single market and customs union to be retained after Brexit.
Mr Drakeford said the Welsh Government supported staying in the customs union as a "transition measure", although he could see it had "downsides as well as upsides".
"I think a number of the views expressed are a reflection of the genuine complexity of the argument," he said.
"Some of the muddying of the water is really a reflection of the fact that the water is genuinely muddy on some of those things.
"Complexity is real and exploring it is not an unhelpful thing to do."
Conservative MP for Brecon and Radnorshire, Chris Davies, said Labour was making "almost hourly shifts in position on Brexit policy".
He added: "Labour should get in a room and try to devise a clear policy or two - they won't, because they can't agree on Brexit and are too busy wandering off in different directions."
On Wednesday, Shadow Chancellor John McDonnell insisted the Labour leadership at a UK level was on the "same page" as Welsh Labour, with tariff-free access to the single market the objective.