Caerphilly fell to their 10th successive defeat of the season as Newport gained victory on the opening day of the new Welsh Premier League.
Newport followed up last Saturday's win over Borders in the Celtic League by scoring five tries for only their second win since early May.
Newport struck first as Mick Voyle won a line-out and a rolling maul sent Jason Forster over in the fourth minute for an unconverted try. The home side were looking for a similar score when Caerphilly halted it illegally and the resultant penalty try was converted by Jason Strange.
It became worse for Caerphilly as the prop Lee Manning was sent to the sin-bin for obstruction, but no score came while he was off the field. Then they lost their captain, Christian Ferris, with injury after 30 minutes before Strange kicked a Newport penalty for a 15-0 lead.
Caerphilly opened the second-half with concerted attacks but Newport survived that period and with Howarth looking the most creative back it was no surprise when he crossed halfway out from a Rod Snow pass with Strange converting.
Caerphilly replied with a smart try by centre Sam Cox, who is on loan from Bath, but Newport soon scored again as Gareth Gravell sped clear and Strange converted.
Newport scored a fifth try two minutes from time from replacement prop Adrian Garvey that Strange converted but Caerphilly went back down field for left-wing Ryan Howells to score their second try.
Newport: S Howarth; A Cadwallager (M Mostyn, 58), H Luscombe, S Williams, L Nabaro; J Strange, O Tonu'u (L Lane, 45); R Snow (D Pattison, 75), J Richards, C Anthony (A Garvey, 53), S Raiwalui (capt), M Voyle (M Veater, 70), S Ojomoh (R Jones, 53), J Forster, G Gravell.
Caerphilly: S Tuipulotu; G Lewis, R Boobyer, S Cox, R Howells; J Thomas, A Chilten; L Manning, C Ferris (capt) (F Vunipola, 30), R Skuse (D Sweet, 58), N Watkins (M Workman, 52), N Rouse, G Jones (G Liddon, 22-30), J El-Abd, A Williams (K Hocking, 52).
Referee: K Evans (Cardiff).