Cape Town - Proteas Test captain Faf du Plessis says he will not make any emotional decisions over his international future.

The 35-year-old has been firmly under the microscope over the last few weeks with the Proteas falling to a 3-1 series loss to England over four Tests.

Along the way, Du Plessis has struggled for form with the bat while his captaincy and field placing have also come under scrutiny.

During an 82-run stand for England's 10th wicket in their first innings of the fourth Test at the Wanderers, for example, Du Plessis went on the defensive and had almost the entire field camped on the boundary in a moment that raised eyebrows.

The Proteas only have two Tests in the West Indies remaining in 2020 and a possible change at the helm has been a strong talking point.

"It feels like you've been pushing me that way the last while," Du Plessis told media in Johannesburg when asked, again, about a potential retirement from either the captaincy or the format as a whole.

"Like I've said to you guys so many times, you don't make decisions like this when you're emotional or disappointed or anything like that.

"I know that right now the results don't look good and certainly from a personal point of view my results this series have been well below par. In order for us to compete as a batting line-up, you need your big players to stand up."

Du Plessis' ODI future is also unclear after captaining the side to 7th place at last year's World Cup and he is not included in a 15-man squad for three matches against England starting early next month.

He is, however, expected to be named in the T20 squad that will follow and has previously identified this year's T20 World Cup in Australia as a possible international swansong.

"For me it's just a bit of time off now to get away from cricket and all the noise," he added.

"Freshen up, then come back for the T20s which will obviously be a full-strength English team and a full strength South African team."

On the criticisms over his captaincy, Du Plessis said he understood where the frustrations were coming from.

"It's very easy to captain when guys can bowl to a plan, but if they don't bowl to the plan then you look like the guy who is doing it wrong," he said.

"I wish that I was so powerful that I could change it, but as captain you can't.

"I don't see it as a reflection of tactically getting it wrong, I see it as a reflection of the performance of the team.

"People want answers when the team is not doing well, and they look to your captain and coach first."